In general, well treatments include a wide variety of methods that may be performed in oil, gas, geothermal and/or water wells, such as drilling, completion and workover methods. The drilling, completion and workover methods may include, but are not limited to, drilling, fracturing, acidizing, logging, cementing, gravel packing, perforating and conformance methods. Many of these well treatments are designed to enhance and/or facilitate the recovery of desirable fluids from a subterranean well.
In cementing methods, such as well construction and remedial cementing, settable compositions are commonly utilized. As used herein, the term “settable composition” refers to a composition(s) that hydraulically sets or otherwise develops compressive strength. Settable compositions may be used in primary cementing operations whereby pipe strings, such as casing and liners, are cemented in well bores. In performing primary cementing, a settable composition may be pumped into an annulus between a subterranean formation and the pipe string disposed in the subterranean formation. The settable composition should set in the annulus, thereby forming an annular sheath of hardened cement (e.g., a cement sheath) that should support and position the pipe string in the well bore and bond the exterior surface of the pipe string to the walls of the well bore. Settable compositions also may be used in remedial cementing methods, such as the placement of cement plugs, and in squeeze cementing for sealing voids in a pipe string, cement sheath, gravel pack, formation, and the like. Settable compositions may also be used in surface applications, for example, construction cementing.
Settable compositions for use in subterranean formations may further include Portland cement. Portland cement generally is a major component of the cost for the settable compositions. Other components may be included in the settable composition in addition to, or in place of, the Portland cement. Such components may include fly ash, slag, shale, zeolite, metakaolin, pumice, perlite, lime, silica, rice-hull ash, micro-fine cement, lime kiln dust, and the like. However, the operating conditions for wells are becoming more challenging and demanding, and the search for new materials continues to meet these challenges.